TORONTO – While a cut on your hand will prompt new skin cells to grow over the wound and heal it, the brain has historically been considered an organ that does not regenerate. If brain cells were lost, they were thought to be gone forever; however, recent studies have suggested that this may not be the case. New research from The Hospital for Sick Children (SickKids) and the University Health Network shows promising results in regenerating neurons in the part of the brain responsible for memory and learning, which may ultimately have applications in neurocognitive diseases like Alzheimer’s. The study is published in the September 21 advance online edition of The Journal of Neuroscience.

Deep brain stimulation, which involves activating electrodes in a targeted area of the brain, has a proven track record of improving symptoms in people with movement disorders like Parkinson’s disease. The technique has been used in more than 60,000 patients. While a preliminary study has shown deep brain stimulation may slow or stop cognitive decline in Alzheimer’s patients, the mechanisms behind this observation remain poorly understood. The research team set out to further explore these mechanisms. The preliminary study was led by co-author Dr. Andres Lozano, Neurosurgeon and Senior Scientist at the Toronto Western Hospital Research Institute and Professor in the Department of Surgery at the University of Toronto.

Dr. Paul Frankland, Principal Investigator of the new study and Senior Scientist in the Neurosciences and Mental Health Program at SickKids, notes “we asked whether increasing the production of new neurons would have any impact on memory and learning. What we found was that we were able to facilitate memory formation.”

Using animal models, the scientists implanted electrodes into the entorhinal cortex, a region of the brain that connects with the hippocampus, where memories are formed. After stimulating the electrodes for an hour, the scientists noticed the production of new neurons in the hippocampus nearly doubled. This increase was observed about three to five days after the deep brain stimulation and lasted about a week. The new neurons that were produced during this period went on to develop and integrate into local circuitry like normal neurons.

Six weeks after the period of increased neuron production, the animal models were trained in a spatial task – finding a hidden platform in a water maze – and showed signs of enhanced memory as they navigated the maze.

To ensure that this improved memory was attributed to the production of the new neurons, and not due to other effects from the stimulation, the scientists used temozolomide (TMZ) to block creation of the new cells. They found that this prevented the memory enhancement, which confirmed that the new neurons are responsible for it.

The research team recently reported early findings on the potential benefits of this type of deep brain stimulation in treating patients with dementia and cognitive impairment. They are currently examining whether the technique can help alleviate cognitive decline in animal models with Alzheimer’s disease.

“Dementia places an enormous burden on society, from the impact it has on the individual and family to the cost of treatment. Efficacious treatments are minimal. Now we may have a way to regenerate parts of the brain and improve its function. This has been one of the dreams of medicine for a long time,” says Lead Author Dr. Scellig Stone, Neurosurgery resident at the University of Toronto.

About The Hospital for Sick ChildrenThe Hospital for Sick Children (SickKids) is recognized as one of the world’s foremost paediatric health-care institutions and is Canada’s leading centre dedicated to advancing children’s health through the integration of patient care, research and education. Founded in 1875 and affiliated with the University of Toronto, SickKids is one of Canada’s most research-intensive hospitals and has generated discoveries that have helped children globally. Its mission is to provide the best in complex and specialized family-centred care; pioneer scientific and clinical advancements; share expertise; foster an academic environment that nurtures health-care professionals; and champion an accessible, comprehensive and sustainable child health system. SickKids is proud of its vision of Healthier Children. A Better World.™ For more information, please visit www.sickkids.ca.

About Peter Gilgan Centre for Research and Learning The Peter Gilgan Centre for Research and Learning will bring together researchers from different scientific disciplines and a variety of clinical perspectives, to accelerate discoveries, new knowledge and their application to child health — a different concept from traditional research building designs. The facility will physically connect SickKids science, discovery and learning activities to its clinical operations. Designed by award-winning architects Diamond Schmitt Architects Inc. and HDR Inc. with a goal to achieve LEED® Gold Certification for sustainable design, the Gilgan Centre will create an architectural landmark as the eastern gateway to Toronto’s Discovery District. The Peter Gilgan Centre for Research and Learning is funded by a grant from the Canada Foundation for Innovation, the Government of Ontario, philanthropist Peter Gilgan and community support for the ongoing fundraising campaign. For more information, please visit www.sickkidsfoundation.com/bepartofit.